Liquid disposal systems are generally used for the evacuation of drainage liquids, usually non-potable wastewater, in a large number of applications. Examples of such applications are found in residence and business building sites that are subject to drainage liquid collection, such as where shallow underground water levels cause wall seepage or where ground water runoff accumulates. Whatever the source of liquid collection, liquid disposal systems find application to pump the collected liquid, which is often non-potable water, to acceptable drainage lines, usually return sewer lines or storm water drainage systems.
Over the past several years, the overall design of pump assemblies for liquid disposal applications has experienced little change. Typically, liquid disposal assemblies can utilize upright, pedestal or fully submersible pumps. Operational pump control has relied upon some form of switch arrangement to detect the presence and level of liquid collected, such as, for example, the level of wastewater in a collection basin. Such switch arrangements have included float rod and ball switches for pedestal pumps; mercury float switches; mechanical float switches; and diaphragm pressure switches. These switch designs have changed little over the past several years and continue to incur well known deficiencies.
Float switch designs are prone to failure due to such factors as wear of mechanical parts; wedging debris entanglement that prevents effective operation; and operational disconnect or maladjustment. With each of these one can expect failure of the pump to maintain a desired liquid level in a collection vessel.
Diaphragm pressure switches rely on the differential movement of a diaphragm having one side exposed to atmospheric pressure and a head pressure on the other side. It is known that such switches can vary in reliability depending on the elevation of the installation, and the breather tubes commonly used to sense atmospheric pressure are often subject to obstruction.
Submersible pumps used in liquid disposal systems are susceptible to failure when the pumping elements become clogged or otherwise frozen. Wastewater reservoirs usually contain debris that is drawn into the pump, and poor pump performance and pump damage follows.
There is a continuing need for an automatic liquid collection and disposal assembly 100 that provides reliable detection of the level of collected liquid and automated control of the pump to reduce the potential for obstruction to the influent of collecting liquid, and which addresses other limitations associated with current prior art assemblies.